The amount of respondents out of all visitors vary from site to site and from industry to industry.
Public facing websites
In our experience, the lowest rates we have seen is about 1 - 2 percent of the visitors usually for public facing websites. When the engagement and commitment to the company or brand are higher than average, the percentage of visitors willing to respond is higher.

Experiment with the collection rateYou can always adjust the collection rate of a survey. You can experiment with the percentage to have more or less visitors interact with your survey.
Learn how Intranet, participation networks and sofort
For internal applications and corporate intranets we have seen response rates up to 40 - 50 percent.
Even with single-digit response rates, our clients find the responses indicative of the experience.